Sub Domains

Don Stokes don at news.daedalus.co.nz
Sun May 21 22:54:38 UTC 2000


Johnno <johnno at nospam.casebook.org> wrote:
>Someone here might be able to point out whether or not name-based hosting
>will correctly work if the DNS entry is a CNAME.

It works fine.  The browser concocts the Host: header (or at least
decides what it's going to put in it) before performing the host lookup,
so it doesn't matter if there's a CNAME in the translation or not.

>When in doubt, use A records.  :-)

That's good advice though.  My usual rul of thumb is to only use CNAMEs
when the alias points outside the administrative unit, eg if your web
side www.example.com points to an external ISP's web hosting service, eg
webserver.isp.net, it's better to use a CNAME so that webserver.isp.net's
address can change without breaking anything.  

Of course tge ISP has to agree not to change the *name* of said box, and
if it does, needs to maintain an A record for the old name, not a CNAME.
So even that call is marginal.

If it's all within the same adminstrative unit, my advice is always to
use A records, and if it starts getting unwieldy, it's time to consider
writing a few scripts etc to maintain the DNS files.

-- don



More information about the bind-users mailing list